I think working with your spouse is a special case, because if your company hits it big (or crashes and burns), then your spouse is likely to share in the joy (

I think working with your spouse is a special case, because if your company hits it big (or crashes and burns), then your spouse is likely to share in the joy (despair) whether or not he or she is officially a co-founder. So if the spouse has some talent that could make the company more likely to succeed, it's not necessarily A Bad Idea for him or her to come on board. This is different from saying "well, Uncle Murray needs a job so I'll hire him to do my bookkeeping"--that's much more likely to be A Bad Idea.